Interestingly, these anti-BP180-NC16A autoantibodies from healthy individuals formed immune complexes with recombinant antigen and dose-dependently activated neutrophils in vitro. 16 samples, anti-BP180-NC16A autoantibody concentrations exceeded the cut-off for the diagnosis of bullous pemphigoid. Interestingly, these anti-BP180-NC16A autoantibodies from healthy individuals formed immune complexes with recombinant antigen and dose-dependently activated neutrophils in vitro. However, fine-epitope mapping within NC16A showed a different binding pattern of anti-BP180-NC16A autoantibodies from healthy individuals compared to bullous pemphigoid patients, while IgG subclasses were identical. Conclusions Collectively, we here report a low prevalence of AIBD autoantibodies in a large cohort of healthy individuals. Furthermore, functional analysis shows differences between autoantibodies from healthy donors and AIBD patients. Electronic supplementary material The online version of this article (doi:10.1186/s13023-015-0278-x) contains supplementary material, which is available to authorized users. Keywords: Autoimmunity, Skin, Type XVII collagen, BP180, Desmoglein, Pemphigoid, Pemphigus Background Autoimmune bullous dermatoses (AIBD) are clinically characterized by chronic mucocutaneous blistering, leading to severe morbidity and increased mortality [1C4]. Blister formation is usually directly or indirectly caused by autoantibodies binding to structural proteins of the skin [5, 6]. Depending on the location of the blister and the targeted autoantigens, AIBD can be classified as pemphigus and pemphigoid disease, epidermolysis bullosa acquisita (EBA) and TUG-891 dermatitis herpetiformis [7, 8]. Epidemiological studies have documented the incidence of AIBD in several geographic regions. In central Europe, bullous pemphigoid (BP) had the highest incidence, with 6.1 to 42.8 cases per million persons per year [1, 3, 4, 9C13]. For pemphigus disease, including pemphigus vulgaris (PV) and pemphigus foliaceus (PF), the reported incidence ranged from 0.6 to 6.8 cases per million persons per year [1, 14C16]. For other autoimmune diseases, studies analyzed serum samples obtained from individuals before they received a diagnosis of systemic lupus erythematousus (SLE) or rheumatoid arthritis (RA). These studies clearly exhibited the presence of autoantibodies several years before diagnosis [17, 18]. Derived from these findings, one may assume that autoantibodies in AIBD also predate the onset of the corresponding disease. However, based on the combined yearly incidence of all AIBD of 0.005?%, to conduct such an investigation with 50C100 AIBD patients would require a predated serum collection of 1C2 million people. In addition, clinically healthy individuals have not been systematically investigated for the presence of autoantibodies to structural proteins of the skin and the reported autoantibody prevalence is usually contradictory. For example, the following autoantibody prevalence rates in healthy populations have been reported: 0C0.7?% for autoantibodies to desmoglein 1 (Dsg) (PF autoantigen); 0C0.2?% for anti-Dsg3 (PV autoantigen); 0-2?% for anti-BP180-NC16A (BP autoantigen); and 0-7?% TUG-891 for anti-BP230 (BP autoantigen) antibodies (Table?1). Therefore, in this study, we aimed at determining the prevalence of autoantibodies against desmosomal and hemidesmosomal structural proteins in a large population of healthy blood donors. In addition, the potential pathogenic relevance of the TUG-891 detected autoantibodies was evaluated. Table 1 Previously reported prevalence rates of autoantibodies to structural proteins of the skin
Dsg1Normal subjects (53)0.0?%[35]Blood donors (401)0.7?%[20]Dsg3Normal TUG-891 subjects (53)0.0?%[35]Blood donors (401)0.2?%[20]BP180*Healthy volunteers (47)0.0?%[36]Blood donors (494)2.0?%[19]Normal subjects (336)1.5?%[37]Healthy subjects (61)0.0?%[38]BP230Normal controls (109)0.0?%[39]Healthy controls (56)7.0?%[40]Blood donors (483)2.1?%[41] Open in a separate windows *to BP180-NC16A if not otherwise noted Methods Blood Donors This study included 7063 normal blood donors from the Institutes for Transfusion Medicine Lbeck, Kiel and Frankfurt between August 2010 and March 2011. All samples were anonymized immediately after blood drawing to comply with requirements by the ethics committees. To avoid duplicate testing of the same person, blood samples from all frequent donors were collected within eight weeks, which is the shortest possible donation interval for men. Further collection was restricted to first-time donors. All plasma aliquots were stored at ?20?C until further testing. All participants signed an informed consent. The study was performed according to the principles of the Declaration of Helsinki and was approved by the local ethics committees (10C094, the ethics committee of the University of Lbeck). Autoantibody screening Plasma samples from all 7063 donors were analyzed for the presence of pemphigus- and pemphigoid-related antibodies with a Rabbit polyclonal to L2HGDH commercial indirect immunofluorescence (IF) assay (dermatology-mosaic 7, EUROIMMUN AG, Lbeck, Germany) at a 1:10 dilution. The assay included the following substrates: primate esophagus, primate salt TUG-891 split skin, recombinant tetrameric BP180-NC16A and transfected HEK293 cells that express recombinant BP230, Dsg1 or Dsg3. Specific fluorescence (Additional file 1).